import { WithIdAndStringIndexer, withIdProps } from "@/fd/fd-toolbox/types/resource-with-id";
import { metaQueryParams } from "@/fd/fd-toolbox/constants/meta-query-params";
import { apiPost } from "@/fd/fd-toolbox/api/api-client";
import { ApiResponse } from "@/fd/fd-toolbox/api/api-response";
import { notify } from "@/fd/fd-toolbox/notifications";
import { routes } from "@/fd/fd-toolbox/routing/routes";
import { FdTableComponent } from "@/meta/table/table-models";
import { getUiResourceMeta } from "@/meta/ui-meta-providers";
import { isString, isObject } from "@/fd/fd-toolbox/types/ensure-type";
import { WithIndexer } from "@/fd/fd-toolbox/types/with-indexer";

interface EmailObject {
    email: string;
}

interface UiResourceMeta {
    resourceMeta: {
        properties: WithIndexer<{ displayName?: string }>;
    };
}

const notifications = {
    noItemsSelected: "Please select at least one item to export",
    exportCompleted: "Items were exported successfully",
};

const csvType = "text/csv";
const defaultFileName = "Export";
const emailProperty = "email";

export function createAndDownloadCsv(data: string, fileName?: string) {
    const blob = new Blob([data], { type: csvType });
    const url = URL.createObjectURL(blob);
    const downloadLink = document.createElement("a");
    downloadLink.href = url;
    downloadLink.download =
        fileName ||
        new URL(window.location.href).searchParams.get(metaQueryParams.resource) ||
        defaultFileName;
    document.body.appendChild(downloadLink);
    downloadLink.click();
    downloadLink.remove();
}

function isEmailObject(obj: unknown): obj is EmailObject {
    return isObject(obj) && emailProperty in obj;
}

function processArrayValue(value: unknown[]) {
    if (value.length > 0 && isObject(value[0]) && emailProperty in value[0]) {
        return value
            .map((obj) => {
                if (isEmailObject(obj)) {
                    return obj.email;
                }

                return String(obj);
            })
            .join(", ");
    }

    return value.join(", ");
}

function processArrayProperties(item: WithIdAndStringIndexer) {
    const processedItem: WithIdAndStringIndexer = { id: item.id || "" };

    for (const [key, value] of Object.entries(item)) {
        if (Array.isArray(value)) {
            processedItem[key] = processArrayValue(value);
        } else {
            processedItem[key] = value;
        }
    }

    return processedItem;
}

function formatItemForExport(item: WithIdAndStringIndexer, uiResourceMeta: UiResourceMeta) {
    const processedItem = processArrayProperties(item);
    const result: WithIdAndStringIndexer = { id: "" };
    const idValue = isString(processedItem.id) ? processedItem.id : String(processedItem.id ?? "");
    let idDisplayName = withIdProps.id;

    for (const [propertyName, value] of Object.entries(processedItem)) {
        const propertyMeta = uiResourceMeta.resourceMeta.properties[propertyName];
        const displayName = propertyMeta?.displayName || propertyName;

        if (propertyName === withIdProps.id) {
            idDisplayName = displayName;
            continue;
        }

        result[displayName] = String(value ?? "");
    }

    result[idDisplayName] = idValue;
    return result;
}

export async function exportItemsInCSVFile(table: FdTableComponent | undefined, resourceName: string) {
    if (!table) {
        return;
    }

    const tableSelectedRows = table.getSelectedRows();

    if (!tableSelectedRows || tableSelectedRows.length === 0) {
        notify(notifications.noItemsSelected);
        return;
    }

    const uiResourceMeta = await getUiResourceMeta(resourceName);
    const items = tableSelectedRows.map(({ item }) => formatItemForExport(item, uiResourceMeta));

    const response = await apiPost<ApiResponse<string>, { items: WithIdAndStringIndexer[] }>(routes.export, {
        items,
    });

    if (response && response.data) {
        createAndDownloadCsv(response.data);
        notify(notifications.exportCompleted);
    }
}